Fetal Development

The development of a life from day 1 to week 40.

Day 1 – Week 2
At conception, the sperm joins with the ovum (egg) to form one cell that contains the complex genetic blueprint for every detail of human development. At this point the child’s sex, hair and eye color, height, and skin tone are already decided.

Week 4
The embryo’s heart has been beating for one week already. The beginning of the spinal cord, muscles, and nerves become apparent. Arms, legs, eyes and ears can now be seen. The amniotic sac and placenta are in place and providing nourishment to the embryo.

Week 6
The eyes begin to form and the extremities can be seen in much more detail, including all ten fingers. The embryo is now moving and responds to touch.

Week 10
At the 9th week the embryo is now considered a fetus. The fetus is able to grasp and can suck his thumb. Fingerprints are already visible in the skin. In addition to being able to sense touch, the fetus can now feel pain. At week 12, the fetus sleeps and awakens.

Week 14
The fetus is growing very rapidly at this point. The mother can now feel energetic movement, and hair is visible on the scalp. Gender becomes apparent by week 13.

Week 18
The ears are now functioning and the baby can hear his or her mother’s voice. By the end of the 4th month, the fetus weighs a half pound or more and is eight to ten inches in length.

Week 22
The head of the fetus now accounts for 1/3 of her length. If this baby were to be born prematurely, she has a chance of survival with intensive medical care.

Week 26
The tongue has formed taste buds and the eyes have fully developed. The baby’s lungs are completely functioning and he can even cry.

Week 30
Vision, hearing, taste, and touch are all being used now. The baby opens and closes her eyes and looks around. Research shows that the child can recognize her mother’s voice.

Week 40
The baby is now ready for life outside of his mother’s womb. By this time, the infant usually weighs six to nine pounds, and his heart is pumping 300 gallons of blood per day.

Sources

A Child Is Born (also in paperback) (book), Lennart Nilsson, Bantam Doubleday Dell, 1990. Order from Amazon.com.